Gomez, who suffers from Lupus, needed a kidney transplant, and her friend, actress Francia Raisa, graciously agreed to donate one of her kidneys (people can survive quite easily with one kidney).

“I’m very aware some of my fans had noticed I was laying low for part of the summer and questioning why I wasn’t promoting my new music, which I was extremely proud of,” she wrote. “So I found out I needed to get a kidney transplant due to my Lupus and was recovering. It was what I needed to do for my overall health.”

In an Instagram post depicting her and Raisa, 29, in adjoining hospital beds, she wrote, “There aren’t words to describe how I can possibly thank my beautiful friend Francia Raisa. She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed. I love you so much sis.”

Now that she’s on the mend, Gomez plans to share more details with her fans about her condition and the operation that saved her life. “I honestly look forward to sharing with you, soon my journey through these past several months as I have always wanted to do with you,” she wrote. “Until then I want to publicly thank my family and incredible team of doctors for everything they have done for me prior to and post-surgery.”